Non-return valves

ABSTRACT

A non-return valve with closure means comprising two movable valve members, one of which is a diaphragm adapted to open rapidly at extremely slight pressures and to seal rapidly at back pressures, while the other valve member is a cover adapted to protect the diaphragm at relatively high back pressures in order to assure sealing engagement also at such conditions.

United States Patent 1191 Hayes ..l37/525 X 1111 3,730,218 I Rydberg 1May 1,1973

[ NON-RETURN VALVES 3,356,100 12/1967 Seeler .137/525 x 1,967,418 7 1934.1137 525 X [75] Inventor: Sverker Rydberg, Mantorp, Sweden 2,747'60941956 "1 375/253 x 3,297,048 1/1967 Imhof ..l37/525 X [73], Assrgnee:System Research Inc., New York, 7

N.Y. FOREIGN PATENTS OR APPLICATIONS [22] Filed: June 26, 1970 865,4157/1949 Germany ..137/s25 409,227 4/1934 Great Britain... ..l37/525.5 pp50,277 367,456 1/1939 Italy ..137/525 Prima Examiner-Robert G. Nilson 30F A t P I orelgn Horny Dam Attorney-Ralph E. Bucknam, Jesse D. Reingold,

July 2, 1969 France 1.6922367 Robert R. Strack and Henry A. Marzullo,Jr.

[52] U.S. Cl ..l37/525 [57] ABSTRACT [51] Int. Cl ..F16k 15/14 Anomretum valve with closure means comprising two Fleld of Search movablevalve members one of is a 137/525] adapted to open rapidly at extremelyslight pressures and to seal rapidly at back pressures, while the other[56] References Cited valve member is a cover adapted to protect thediaphragm at relatively high back pressures in order to assure sealingengagement also at such Conditions.

5 Claims, 2 Drawing Figures Patented May 1, 1973 FIG! NON-RETURN VALVESThis invention relates to a non-return valve of the type having apreferably circular diaphragm of elastic material such as rubber, saiddiaphragm having the shape of a concave-convex lens the concave side ofwhich faces a planar seat.

The general object of this invention is to provide an improvedpressureoperated non-return valve which will open at extremely slightpressures and which is adapted to close rapidly at slight back pressuresand to withstand even relatively high back pressures without collapse ofthe diaphragm.

Another object of the invention is to provide an inexpensive, efficientnon-return valve of the type described.

Still another object of the invention is to provide a non-return valveby which it is possible to reduce the pressure difference necessary foropening the .valve, andparticularly to fractions of 1 mm water column.

Accordingly, it is an object of the invention to provide a non-returnvalve comprising a base member provided with a valve port and a valveseat surrounding said port, and a closure means including a pressureoperated diaphragm supported on said valve seat and a cover supportedabove the diaphragm. The diaphragm is formed of elastic material intothe shape of a concave-convex lens which in closed valve positionsealingly engages said valve seat with its margin and with the concaveside of the diaphragm facing the valve port. The valve comprises firstconnecting and supporting means movably connecting the cover to thediaphragm,.the cover being formed with a surface facing the diaphragmand adapted in the operative position thereof to pressthe diaphragmagainst the valve seat. The valve includes second connecting andsupporting means for connecting the cover to the base member and forsupporting the cover, in inoperative position, at a predetermineddistance from the valve seat, the diaphragm having an extremely thinmarginal portion which is adapted to be seated and unseated by extremelylight positive pressure difference acting on the convex and concaveside, respectively, of said diaphragm. The connecting means are formedof elastic material and are dimensioned and constructed in such a manneras to permit a positive pressure difference on the convex side of thediaphragm and on the outer side of the cover to deform the diaphragm inan inward direction towards the valve port to move the cover intoengagement with said diaphragm to press it against the valve seat and bycovering the latter, relieve the pressure load on said diaphragm.

Another object of the invention is to provide a nonreturn valve of thetype described. in which said supporting and connecting means forconnecting said cover to said base member and for supporting said covercomprise at least one pair of diametrical U-bent elements of elasticmaterial.

Still another'object of the invention is to provide a non-return valveof the type described, in which said supporting and connecting means forconnecting said cover to said base member and for supporting said covercomprise at least one pair of diametrical U-bent elements of elasticmaterial. said elements being formed with weakened portions such asholes.

A further object of the invention is to provide a nonretum valve of thetype described, in which said first connecting and supportingmeans forconnectingthe cover to said diaphragm and for supporting said covercomprise an extension on the convex face of said diaphragm; said coverhaving a recess in the side thereof facing said diaphragm; and a head atthe end of said extension received in said recess, said extension beingadapted to drawsaid cover nearer the valve seat whenever said diaphragmis defonned by a pressure acting on the convex side thereof, and inwhich said second connecting and supporting means are adapted to allowsaid pressure to force the cover against the diaphragm for relieving thepressure load thereon.

Particularly useful embodiments of the non-return valve arecharacterized in that the seat is formed by the flat end surface of aplug of elastic material such as rubber, said plug having a central borein communication with said valve port and in which there can be fixe anexternally threaded tubular socket.

Characteristic of a non-return valve of this type is that it operates atrelatively slight pressure differences and ensures a perfect seal inspite of a relatively high back pressure.

It has been found desirable, however, to further reduce the pressuredifference necessary for opening the valve.

The pressure difference necessary for opening the valve, according tothis invention, isa function of'the stiffness of the elastic supportingand connecting means, such as the proportion of the diameter of thethrough holes to the sections of the elastic supporting and connectingelements. One advantage of the inven tion is that the valve closuremeans-is able to operate very rapidly and is nevertheless able towithstand high back pressure without collapse of the diaphragm.

These and further features of, as well as the advantages gaihed by, theinvention will become apparent from the following description in whichreference is made to the accompanying drawings in which:

FIG. 1 is a side view of an embodiment of the nonreturn valve accordingto the invention;

FIG. 2 is a plan view thereof.

The valve comprises a base member in the form of a material having anelasticity similar to rubber and with a central hole 2 in it. Anexternally threaded tubular socket 3 of metal or hard synthetic plasticis inserted in the hole 2. The upper end of this hole 2 serves as avalve port and issurrounded by a planar surface 10 at the upper end ofthe plug. This planar surface 10 serves as a valve seat. The plug 1 hasa flat outer end and two laterally projecting U-shaped elements ortongues 4 which at a given distance from the edge of the plug 1 areprovided with stiffening webs in the bend 5 of the U. The upper limb ofeach tongue 4 extends inwardly to and is connected with a cover 6 in.the form of a cup of relatively thick and rigid material, such asplastic, while the lower limb of each tongue extends to and is connectedwith the plug 1. At least that side of the cover 6 facing the plugconsists of an elastic material, preferably with an elasticity similarto rubber, and preferably it has a flat inner side. The cover isattached to the tongues in such a way as to be kept at a certaindistance from the outer smooth face 10 of the plug 1 when the cover 6 isnot subjected to load.

At its inner side the cover 6 has a central recess 7 which conicallywidens inwardly.

As shown in FIG. 1 there is seated on the valve seat of the plug 1 adiaphragm 8 of a material having an elasticity similar to rubber andshaped as a concaveconvex lens, the concave side of which faces the flatvalve seat 10. The diaphragm 8 has an extremely thin marginal portionthe edge of which engages the valve seat 10 in closed valve position.The diaphragm 8 is provided on its outer side with a projection 9 in theform of an inverted frusto-conical shank fitting the recess 7. Thediameter of the projection 9 is not critical but is preferably smallerthan that of the hole 2. The

diameter of the diaphragm 8 is of course larger than that of the hole 2but is smaller than that of the outer face 10 of the plug 1.

As shown on the drawings there is formed in each limb of each U-benttongue 4 a weakening hole 11 the function of which will be describedbelow.

The non-return valve described above functions as follows:

In its unloaded state the diaphragm 8 is maintained by the projection 9in a position in which it engages the outer face 10 of the plug with itsextremely thin marginal portion. When a pressure is exerted on the innerside of said diaphragm 8, for example by a fluid to be dischargedthrough the hole 2, the marginal portion of the diaphragm 8 is firstunseated from said outer face 10 of the plug, and in case of a high flowrate and pressure the cover 6 and the entire diaphragm are alsounseated. In the case of suction acting on the inner side of thediaphragm 8 the marginal portion thereof will sealingly engage the outerface 10 of the plug 1 even at an extremely slight pressure difference.When the pressure difference increases the projection 9 will move thecover 6 towards the outer face 10 of the plug 1, and the pressure willthen force the cover 6 tightly against the diaphragm, whereupon thecover 6 will relieve the diaphragm of the entire pressure difference.

By providing the holes 11 in the tongues 4 it is possible to reduce thepressure difference necessary for opening the valve. 8

Of course the invention is not restricted to the embodiment describedabove and shown in the drawings since various modifications may beresorted to within the scope of the appended claims.

What I claim and desire to secure by Letters Patent 1. A non-returnvalve comprising a base member provided with a passage, a planar memberabove said passage serving as a valve seat, a diaphragm supported bysaid planar member, said diaphragm consisting of a concave-convex memberof elastic material, said diaphragm having a thin marginal portion andbeing wider than said passage, a cover element supported above thediaphragm, first elastic means connecting said'cover element to thediaphragm and supporting the cover element, second elastic means forsupporting the cover element and for connecting said cover element tosaid base member, said second means comprising at least one pair ofU-bent elements, the diaphragm being responsive to small pressuredifferences, being seated against said planar member under the action ofa positive pressure on its convex side and being unseated therefrom,while the cover is being held at a predetermined distance under theaction of pressure on the inner concave side of said diaphragm.

2. A valve according to claim 1 wherein said U-bent elements arediametrical.

3. A valve according to claim 1 wherein each of said U-bent elementscontains a hole.

4. A valve according to claim l wherein said first elastic meanscomprise a projection on the convex surface of the diaphragm and arecess on the cover element, said projection being adapted to engagewith said recess to draw the cover element closer to said planar memberunder the effect of pressure on the convex side thereof.

5. A valve according to claim 4 wherein said projection has diametersmaller than the passage within said base member.

1. A non-return valve comprising a base member provided with a passage,a planar member above said passage serving as a valve seat, a diaphragmsupported by said planar member, said diaphragm consisting of aconcave-convex member of elastic material, said diaphragm having a thinmarginal portion and being wider than said passage, a cover elementsupported above the diaphragm, first elastic means connecting said coverelement to the diaphragm and supporting the cover element, secondelastic means for supporting the cover element and for connecting saidcover element to said base member, said second means comprising at leastone pair of U-bent elements, the diaphragm being responsive to smallpressure differences, being seated against said planar member under theaction of a positive pressure on its convex side and being unseatedtherefrom, while the cover is being held at a predetermined distanceunder the action of pressure on the inner concave side of saiddiaphragm.
 2. A valve according to claim 1 wherein said U-bent elementsare diametrical.
 3. A valve according to claim 1 wherein each of saidU-bent elements contains a hole.
 4. A valve according to claim 1 whereinsaid first elastic means comprise a projection on the convex surface ofthe diaphragm and a recess on the cover element, said projection beingadapted to engage with said recess to draw the cover element closer tosaid planar member under the effect of pressure on the convex sidethereof.
 5. A valve according to claim 4 wherein said projection hasdiameter smaller than the passage within said base member.